(a) Field of the Invention
The present invention relates to an encryption/decryption device in a wireless local area network (WLAN) and a method thereof. More particularly, the present invention relates to an encryption/decryption device using an RC4 algorithm for an encryption/decryption of RSNA 802.11 WLAN and a method thereof.
(b) Description of the Related Art
Recently, a series of standards for IEEE 802.11 wireless LAN technology developed by working groups of the IEEE have been focused on. Particularly, a Wired Equivalent Privacy (WEP), a Temporal Key Integrity Protocol (TKIP), and a Counter with CBC-MAC Protocol (CCMP) have been largely developed among components composed of an encryption/decryption IP of a Robust Security Network Association (RSNA) 802.11 WLAN.
Generally, the WEP is a security standard defined so as to supply security of the wire LAN-level for WLAN, and it uses encryption of an RC4 scheme and a CRC32 scheme so as to ensure integrity and secrecy for a link layer.
The TKIP is a security standard of a next generation WLAN, and generates different WEP seed keys for the respective packets according to a Transmitter Address (TA) and a TKIP Sequence Counter (TSC) and performs encapsulation and decapsulation on the different WEP seed keys using an RC4 encryption algorithm such as the WEP. Conventional WEP hardware is available to the existing encryption/decryption as it is currently given, and may further be used with software modification.
In addition, the CCMP is a security standard protocol of a next generation WLAN, and provides data secrecy, data integrity, and integrity of a selective header value using an AES-CCM encryption algorithm.
For such encryption/decryption, Korean Patent Publication No. 2003-0061159 discloses hardware for an IEEE 802.11 MAC web algorithm, that is, hardware for rapidly processing the WEP algorithm. According to the prior art, in order to minimize a delay of a frame processing time according to the WEP operation, the WEP algorithm is realized by configuring a state table in the form of a register file so that a secret key is determined to finish a key setup phase during 256 hardware cycles and generate 1 pseudo-random number during 1 hardware cycle. In addition, the state table generates a pseudo-random number to be used for encrypting/decrypting data. An operation for swapping values of the state table occurs on initializing the state table and generating a pseudo-random number. However, when the state table is used in form of the register file, the swapping operation is finished during 1 hardware cycle thereby minimizing the delay of the frame processing time.
Meanwhile, Korean Patent Publication No. 2003-0078453 discloses a method for encrypting/decrypting data in a WLAN and a device thereof. Particularly, in order to overcome a drawbacks of the WEP scheme used in the IEEE 802.11 standards, the method for encrypting/decrypting data in a WLAN and a device thereof performs XOR operation with the key sequences generated using an Integrity Check Value (ICV) as a seed and the transmitted data so that the external cannot tap and perceive the transmitted data.
However, in such an encryption/decryption algorithm, the WEP seed key is generated through the key mixing process, and the key scheduling process is performed using the WEP seed key in the RC4 encryption algorithm to generate S-Box data. These key mixing and scheduling processes, etc., are performed previous to the encryption/decryption process, whenever the respective data are processed. Accordingly, much time for preparing these processes is needed, that is, a waiting time is required for the encryption/decryption process.
Ultimately, a method for reducing the waiting time is required so as to rapidly encrypt/decrypt data in a WLAN system.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.